A195328 Number of bases to which terms of A141768 are strong pseudoprimes.

2, 4, 6, 18, 50, 54, 162, 242, 450, 486, 882, 1058, 1782, 3042, 3078, 4050, 5202, 9522, 19602, 22050, 36450, 46818, 54450, 66978, 71442, 95922, 124002, 149058, 183618, 190962, 238050, 240570, 263538, 277830, 328050, 466578, 684450, 816642, 977202

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..5476

Index entries for sequences related to pseudoprimes

Prog

(PARI) star(n)={n--; n>>valuation(n, 2)};
bases(n)=my(f=factor(n)[, 1], nu=valuation(f[1]-1, 2), nn = star(n)); for(i=2, #f, nu = min(nu, valuation(f[i] - 1, 2)); ); (1 + (2^(#f * nu) - 1) / (2^#f - 1)) * prod(i=1, #f, gcd(nn, star(f[i]))); \\ Given a value of A141768, this function transforms it to a term of this sequence.

Crossrefs

Cf. A141768, A195327.

Sequence in context: A066894 A233919 A111115 * A294447 A143085 A304756

Adjacent sequences: A195325 A195326 A195327 * A195329 A195330 A195331

Keyword

nonn

Author

Charles R Greathouse IV, Sep 15 2011

Status

approved